This invention relates to packaging in general and in particular to box blanks for pizza cartons and other food cartons made of semi-rigid, foldable material.
In the pizza and food-to-go industries there are numerous types of cartons made of foldable material. Perhaps the most prevalent of these materials is corrugated paperboard. Cartons made of corrugated paperboard are erected from a flat sheet of material known as a box blank, or blank, for short.
At least three problems exist with many of the current types of blanks used for pizza and food cartons. First, the blank can require a relatively large amount of material, particularly the blanks for those cartons that utilize the traditional double-panel, or roll-over, front wall structure.
Second, during manufacture, corner flaps attached to the ends of side walls at a fold line tend to bend at the fold line as the blanks are released from the cutting dies and as they proceed down the production line. This is especially the case with blanks made of thinner types of corrugated paperboard, such as E-flute and F-flute. A folded, or unaligned, flap can cause problems in production, sometimes requiring the production line to be slowed down or stopped.
Third, some blanks use a cover-locking structure that involves inserting a cover front flap into a flap-receiving slot in the front wall of the carton. In order for the slot to tightly grip the cover flap, the slot must be relatively narrow in the front-to-back, or width-type, dimension. However, with this configuration it can be difficult and time-consuming to fit the cover flap into the slot. To make it easier to quickly fit the cover flap into the slot, a wider flap-receiving slot can be used. However, when this is done the slot often fails to tightly grip and hold the cover flap in place, particularly after the carton has been opened and then re-closed.
Regarding the first problem (i.e., use of excessive material for making the blank), box manufacturers have designed the structure of box blanks so that multiple side-by-side blanks mate, or nest, together during the die-cutting phase of manufacture. This reduces the amount of material needed for manufacture of each blank. The process of mating adjacent blanks has been used as a material-reduction technique for the last hundred years or so. As a result, hundreds of mated side-by-side arrangements of multiple blanks have been invented. However, no arrangement has been created that accommodates the typical structure of a pizza carton or food carton. That structure comprises a bottom panel, a rear wall attached to the bottom panel, a cover panel attached to the rear wall, a cover front flap attached to the front edge of the cover panel, and a front wall structure opposing the rear wall and comprising a front wall and an ancillary panel structure attached to the front wall. So there has remained a need for a mating arrangement for typical food carton box blanks that effects a savings of material in manufacture of the blanks.
Regarding the second problem (i.e., the folding or misalignment of corner flaps during blank manufacture), the typical solution has been to create a xe2x80x9ctack,xe2x80x9d or narrow strip of material, between the flap and an adjacent panel of the blank. However, this requires the end-user to have to take the time to break the xe2x80x9ctackxe2x80x9d before erecting the blank into a box. As a result, there has remained a need for xe2x80x9crigidizedxe2x80x9d corner flaps on a box blank without resorting to the inconvenient xe2x80x9ctack.xe2x80x9d The typical fold line used for connecting a corner flap to a, wall panel consists of either (a) a score (i.e., crease) in the board or (b) a series of aligned slits, sometimes referred to as a perforation line, or perf line. A fold line of aligned slits usually takes the form of either one-quarter inch slits separated by a one-quarter inch score or one-eighth inch slits separated by a one-eighth inch score. There has been no inventive prior art pertaining to fold line structure. So there has remained a need for a fold line structure that results in rigidizing or holding corner flaps in place during manufacture of the blank.
Regarding the third problem (i.e., lack of a slot-forming structure that results in a flap-receiving slot that""s both easy to insert the cover flap into and tight-gripping enough to hold the flap within the slot once it""s inserted), as regards double-panel wall structures where an inner wall panel is disposed parallel to an outer wall panel, there has been no inventive prior art pertaining to cover flap receiving slots. So there has remained a need for a slot-forming structure that results in a flap-receiving slot that is both easy to use and tight-gripping of the cover flap.
Accordingly, it would be highly desirable to provide a box blank that overcomes one, two, or all three of the above-described problems. None of the three problems have been solved by the prior art, but they are solved by my invention.
My invention is a box blank that provides one or more of the following three features:
1. End-to-end mating of multiple blanks wherein a cover front flap of a first blank is disposed within a notch in the front wall structure of a second blank, thereby effecting a savings of material;
2. A rigidizing fold line used in attaching a flap to an end of a wall panel, wherein the rigidizing fold line comprises at least one indentation portion and at least one non-indentation portion, thereby reducing movement of the flap while in the manufacturing process; and
3. A frictionizing slot-forming slit disposed within a multi-panel wall structure of a box blank, wherein the frictionizing slot-forming slit has a central-slit portion and at least one end-slit portion that""s disposed at an obtuse angle to the central-slit portion, thereby providing for a trapezoidal-shaped flap-receiving slot with an acutely angled end section in the erected carton, and which, in turn, enables the slot to grip, or pinch, the side edge of a cover flap and hold it within the slot.
My invention typically would be associated with blanks used for creating cartons for food products; however, it could take other forms for other purposes, as well.
A complete understanding of the invention can be obtained from the detailed description that follows.
The main object of my invention is (a) a material efficient box blank that""s (b) easy to manufacture and (c) which provides for a cover-locking slot that allows for easy cover flap insertion while also providing a tight grip on the flap.
The advantages of my invention are cost savings, production simplicity, and cover closure enhancement on a food carton.
Further objects and advantages of the invention will become apparent from consideration of the following detailed description, related drawings, and appended claims.